Question 249334
.60*20+.10x=.50(20+x)
12+.10x=10+.50x
.10x-.50x=10-12
-.4x=-2
x=-2/-.40
x=5 gallons of 10% salt solution is added.
Proof:
.60*20+.10*5=.5(20+5)
12+.5=.5*25
12.5=12.5